The present invention relates to the technology of pipetting, and more particularly to a pipette used to accurately measure and deliver, by suction, known volumes of liquids or solutions and which includes an improved body, a tip removably attached to the body and having formed at the front end thereof an inlet/outlet hole through which a liquid is sucked up and delivered and an opening formed at the top end thereof, and means for sucking air from inside the pipette tip or supplying air into the pipette tip.
In the conventional pipette, the pipette tip has formed at the top end thereof an opening whose inside diameter of 4, 5, 8.5, 11 or 13 mm, and a nozzle cone corresponding to each inside diameter of the opening is attached to the pipette body. The nozzle cone is elastic, and formed to have a size corresponding to the diameter of each pipette tip. The nozzle cone is fitted onto the pipette tip from the opening at the top end of the pipette tip (to plug up the opening) to keep sealed the pipette tip while it is being fitted on the pipette tip. An air passage is formed through the nozzle cone and pipette body. To measure and deliver a given volume of a liquid or solution into the pipette tip, air is sucked out from inside the pipette tip through the air passage. On the contrary, to discharge the liquid measured and sucked up in the pipette tip, air is supplied into the pipette tip through the air passage.
Generally, many of the pipette tips are made of polypropylene and majority of them are of a disposable type. Therefore, if the inside diameter of the pipette tip is varied or if the outside diameter of the nozzle cone is varied, the contact of the nozzle cone with the inner wall of the pipette tip is varied correspondingly and thus the adherence and air-tightness become poor. When a liquid is discharged at a high speed or when a highly adhesive liquid is discharged, the pressure inside the pipette tip will be elevated. To withstand such a high pressure inside the pipette tip, the adherence of the nozzle cone to the pipette tip has to be higher. Further, in case the adherence of the nozzle cone to the pipette tip is made higher in the conventional pipette of a type in which the nozzle cone is fitted in the pipette tip, there is a likelihood that the nozzle cone cannot easily be attached to or removed from the pipette tip.
The present invention has an object to overcome the above-mentioned drawbacks of the prior art by providing a pipette in which a pipette tip can securely be fitted to a pipette body with a high adherence and easily be attached to or removed from the pipette body even if the inside and outside diameters of an opening formed at the top end of the pipette tip vary.
The above object can be attained by providing a pipette in which a tip having formed at the front end thereof an inlet/outlet hole through which a liquid is sucked up and delivered, is fitted at an opening formed at the top end thereof on a body having formed therein an air passage through which air is sucked out from inside the pipette tip or supplied into the pipette tip, the pipette including:
an inflatable member secured to the pipette body and which can be inflated with a fluid charged therein;
the pipette body having formed therein separately from the air passage, a fluid passage through which a fluid is charged and discharged; and
the inflatable member being to be charged with the fluid through the fluid passage in the pipette body and thus inflated for close adherence to the inner wall or outer surface of the top end portion of the pipette tip where the opening is formed, to thereby securely catch the pipette tip.
The object and other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments of the present invention when taken in conjunction with the accompanying drawings. It should be noted that the present invention is not limited to the embodiments but can freely be modified without departing from the scope and spirit thereof defined in the claims given later.